I currently live in a house of unknown age. There are four bathrooms (it is not as glamorous as it may sound). When flushing the toilets from the second and third floors the pipes, they make a horrible screeching sound. Similar to the sound metal may cry out if it is being twisted. I have never heard such a sound in any house i have ever been in. This has only begun in the past few months. Any help would be greatly appreciated.